As disclosed in JP-B-39-10923 (the term "JP-B" as used herein means an "examined Japanese patent publication"), a process has heretofore been known which comprises the reduction of 3-cyano-3,5,5-trimethylcyclohexanone in the presence of ammonia, a catalyst and hydrogen to produce 3-aminomethyl-3,5,5-trimethylcyclohexylamine. However, the preparation process is disadvantageous in that the reaction occurs under an extremely high pressure and that a silicic acid-supported cobalt catalyst must be reduced and crushed immediately before use.
This reaction is also disadvantageous in that it is extremely difficult to avoid the production of 1,3,3-trimethyl-6-azabicyclo[3,2,1]octane (hereinafter referred to as "bicyclo compound") as a by-product by intramolecular cyclization attributable to the structural characteristics of the starting material as described in JP-A-3-47156 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"). This is a main cause that lowers the yield of the desired compound.
Further, JP-B-62-123154 proposes the use of Raney cobalt catalyst as a catalyst. The use of Raney cobalt catalyst allows the reaction to proceed under mild conditions. However, Raney cobalt catalyst has a problem in that it has the property of catching fire in the air and thus needs to be carefully treated.
Thus, there have been problems which must be solved in the actual industrial process for the preparation of a 3-aminomethyl-3,5,5-trialkylcyclohexylamine.